strstr()函数 [英] strstr() function

问题描述

我正在尝试编写一个程序，将用户输入的子字符串与字符串数组进行比较.

I am trying to write a program that compares a substring that the user enters with an array of strings.

#include <stdio.h>
#include <string.h>

char animals[][20] = {
    "dogs are cool",
    "frogs are freaky",
    "monkeys are crazy"
};

int main() {
    char input[10];

    puts("Enter animal name: ");
    fgets(input, sizeof(input), stdin);

    int i;
    for(i = 0; i < 3; i++) {
        if(strstr(animals[i], input))
            printf("%s", animals[i]);
    }
    return 0;
}

例如，当我输入青蛙时，它应该打印青蛙怪胎"消息，但什么也不会输出.

When I enter frogs, for example it should print the message "frogs are freaky", but it prints out nothing.

因此，我尝试写一行以每次打印出strstr()函数的值，并且它们都返回0，这意味着所有比较都失败了.我不明白为什么，有人可以帮我吗?

So I tried to write a line to print out the value of the strstr() function each time and they all returned 0, which means all the comparisons failed. I don't understand why, can someone help me please?

推荐答案

这是因为您的字符串包含换行符.

This is because your string contains the newline character.

从 fgets文档:

换行符使fget停止读取，但是该函数将其视为有效字符并包含在复制到str的字符串中.

A newline character makes fgets stop reading, but it is considered a valid character by the function and included in the string copied to str.

这应该可以解决问题(演示):

This should fix the problem (demo):

#include <stdio.h>
#include <string.h>

char animals[][20] = {
"dogs are cool",
"frogs are freaky",
"monkeys are crazy"
};

int main() {
    char input[10];

    printf("Enter animal name: ");
    scanf("%9s", input);

    int i;
    for(i = 0; i < 3; i++) {
        if(strstr(animals[i], input))
            printf("%s", animals[i]);
    }
    return 0;
}

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